Eraser for vellum xerographic copy paper

ABSTRACT

An eraser composition for the removal of toner from translucent vellum xerographic copy paper comprising a wax binder containing a uniformly distributed abrasive. The advantage of the eraser composition is that it does not smudge the toner or abrade the surface of vellum xerographic copy paper, and therefore allows copies to be reproduced by diazo-type processes with no indications of erasures in the final copies.

United States Patent MacClaren 1 51 Feb. 29, 1972 [54] ERASER FOR VELLUM XEROGRAPHIC COPY PAPER [52] US. Cl ..51/28l, 51/304, 51/305 {51] Int. Cl ..B24b l/00 [58] Field ofSearch ..51/305,281,293,304

[56] Reierences Cited UNITED STATES PATENTS 1,593,062 7/1926 Cook 51/305 1,602,437 10/1926 Kazda.... 51/305 1,750,288 3/1930 Stewart.. ..51/305 1,813,675 7/1931 Moore ..5 H305 Cortes Young Lewis Davidson Soderberg..... Sarofeen Primary Examiner-Donald J. Arnold Attorney-James J. Ralabate, Donald F. Dale and Robert W. Mulcahy 1 ABSTRACT An eraser composition for the removal of toner from translucent vellum xerographic copy paper comprising a wax binder containing a uniformly distributed abrasive. The advantage of the eraser composition is that it does not smudge the toner or abrade the surface of vellum xerographic copy paper, and therefore allows copies to be reproduced by diazo-type processes with no indications of erasures in the final copies.

5 Claims, No Drawings ERASER FOR VELLUM XEROGRAPIIIC COPY PAPER BACKGROUND OF THE INVENTION The present invention relates to an eraser for xerographic toner and in particular an eraser for the removal of toner from translucent vellum xerographic copy paper.

It has been difficult for draftsmen and engineers to reproduce old and worn plans or sketches. Draftsinen have a special problem in that their plans or sketches are generally very large and are used numerous times after which they become worn, wrinkled, and blemished. Another problem associated with these large scale sketches is their use in a new series of plans or models; that is, if one wanted to use the sketch as a basic plan for a new model the original plan had to be reprinted over again. The use of conventional office-type copy machines for said sketches have been precluded because of the size of the large scale sketches.

Through the art of xerography, however, a remedy has been found for the reproduction of large scale sketches. In xerographic reproduction, an electrostatic latent image is formed by uniformly charging a photoconductive insulating surface of a xerographic plate followed by exposing the charged surface to a pattern of light. The latent image formed by this technique is then developed as electroscopic powder, also known as toner, to form a powdered image which is then transferred to a sheet of paper. The powder image contained on the paper is then fused into the paper to form a permanent reproduction of an original image. By means of this process it is possible to copy only the print of the wrinkled and blemished large scale sketches mentioned above, and thereby eliminate all blemishes in the final xerographic copy In the Xerox 1824 Machine it has been possible to reproduce copies of large cumbersome sketches which are in fact of better visual quality than the original drawing.

While xerographic reproduction of large scale sketches are indeed satisfactory, draftsmen often desire blueprints of or other color prints of the corrected copy of their original drawing; that is, for purposes of particular use, diazo-type reproductions are required of the clean xerographic copies. The diazo-type process is based on three qualities of certain organic chemicals which belong to the family of the diazocompounds: (1) Their reaction with ultraviolet light to decompose to a colorless product; (2) their relative stability to an acidic medium; and (3) their capacity to couple under alkaline conditions, i.e., to react with other types of organic compounds formally called couplers, to form azo dyes. The most widely used process utilizes a so called two component or dry process material which contains the diazo compound and the coupler in the surface layer of the copy sheet and uses an exposure to ammonia for print development. In carrying out the process of this type on a commercial machine such as the Bruning Revolute 880, a drawing up to 42 inches in width, by any length, on translucent tracing paper is introduced along with the sensitized paper into the machine. The drawing is then exposed and a print made provided the original is sufficiently translucent for the powerful light source to penetrate it and providing the image once original has sufficient density to absorb at least a part of the light before it reaches the sensitized material. After exposure, the original is automatically separated from a sensitized material the the latter is conveyed to a developer where a chemical reaction with ammonia completes the process to produce the flash print. The printis then delivered to a tray at either the front or rear of the machine.

The aforementioned procedures of making a xerographic copy of an original large scale drawing and thereafter subjecting said copy to diazo-type reproduction has had great success among draftsmen and engineers. However, there is a recurrent problem in the two step procedure in that in orderto insure a diazo-copy of the clean xerographic reproduction the xerographic copy has to be made on vellum tracing paper, which is translucent, and any attempt to modify or change the xerographic copy by erasing the toner deposits results in smudging of the toner of, if more than very light pressure is applied, abrasion of the paper such that its fibers emerge. Consequently when such a smudged or abraded translucent vellum is then subjected'to the diazo-type process the disturbed portions of the copy are opaque and hence appear as a distortion on the final diazo print. This problem invariably occurs when one attempts-to remove the fused toner from the surface of the translucent vellum xerographic copy paper.

OBJECTS OF THE INVENTION It is therefore an object of the present invention to provide an effective and inexpensive means of erasing translucent vellum xerographic copy paper.

Another object of the invention is to provide an eraser comprising a wax binder matrix having an abrasive uniformly dispersed throughout said matrix.

A further object of the instant invention is to provide an eraser composition for the removal of toner from translucent vellum xerographic copy paper without smudging the toner or disturbing the fibers of the paper.

BRIEF DESCRIPTION OF THE INVENTION This invention relates to a particular composition which enablesthe removal of fused toner from vellum tracing paper without smudging toner or abrading the surface. The present invention contemplates a composition comprising a binder material such as wax and an abrasive such as silica gel. The ratio of abrasive to binder in the present composition should be such that the abrasive is well dispersed throughout the binder, .i.e., a uniform and dilute dispersion of abradant material is required to insure against raising the fibers in the vellum xerographic copy. The binder and the abradant ingredientsmay be compounded with the aid of heat and after thorough mixing formed into any desired shape for its ultimate use as an eraser for vellum paper. In addition, other ingredients such as dessicants or softening agents may be employed in the present invention.

Optimum results are obtained with the composition of the present invention by having it cylindrically encased by the particular wax matrix material used in the composition. As will be shown heretofore, application of the centrally located eraser composition to vellum paper is facilitated because upon rubbing the peripheral wax casing additionally smooths any raised fibers.

For purposes of the present invention any well-known organic or inorganic binders may be used. Typical binders are waxes, both natural and synthetic, tallows, stearic acids and synthetic resins. Inasmuch as waxes are inexpensive and readily available they are the most preferably binders. The natural waxes which are most suitable for the present purposes are paraffin, Cerasin, ozokrite, Utah wax, microwax, and pure beeswax. Similarly, synthetic waxes such as polyethylene glycol can be used. As mentioned above, there should be a large proportion of wax to abrasive in the composition. Generally, the proportion of wax should exceed 60 percent by weight of the total composition and preferably should be between 70 and 90 percent by weight wax binder material.

Suitable abrasive for the present composition can be any material whichis conventionally used as an abrasive. lnorganic abradant materials such as fused aluminum oxide powder, finely powdered pumice, silica gels or solids, glass frit and glassfibers are acceptable for use as the abradant substances in the eraser composition of the present invention and are utilized in ranges from about to40 percent. Organic abradant matter such asground comhusks, soya bits, almond meal and the like may also be used in similar ranges of from about 20 to SOpercent. Conventional mesh sizes (openings per square inch which will retain the substance) for various abrasivcswhich have provedsatisfactory are the following ranges: pumice, 100 to 300;.alumina, 100 to 300; soya bits, 40 to 300; almond meal, 100 to 300; ground comhusk, 10 to 300', and silica, 100 to 300. While any and all abrasives are within the purview of the present invention, the inorganic abrasives are preferred because of their availability and ease of mixing with a wax material.

In the preparation of the improved vellum eraser composition of the present invention the particular wax to be used as a binder, or mixtures thereof, is first melted. After the wax has liquified a dessicant such as sulfur is added to the melt. After the dessicant and wax are completely mixed a dispersing agent and from about to 30 percent of abrasive are added to the melt and the entire mixture is cooled with stirring to between 50 and 75 C. and poured into any conveniently shaped molds or dispensing containers for the eraser. Upon cooling, the eraser sticks or blocks are placed in a suitable convenient holder or dispenser if they are not molded therein initially.

The resulting product is a stick or block-type applicator eraser which obviates the need for cloth, sponge, or digital application to the areas to be corrected on the vellum xerographic copy paper. Further, the eraser may be applied directly to those areas to be corrected without exerting excessive pressure which tends to raise the paper fibers. However, as pointed out above, the eraser composition is further enhanced by encasing the stick in the particular wax material used in the eraser composition.

As already mentioned, the present invention contemplates a binder composition having an abrasive material uniformly dispersed throughout the eraser material. Furthermore, the abrasive must be in a low concentration such that there is very little likelihood of a serious buildup of abradant material in any one area of the eraser composition with passage of time; that is, with applied pressure on an eraser of high-abrasive composition there is a tendency for a buildup of the abradant thereby resulting in it being excessively grating.

DESCRIPTION OF PREFERRED EMBODIMENT For purposes of affording those skilled in the art a better understanding of the invention, the following illustrative examples are given:

The waxes are mixed together and heated to 70 C.; the sulfur is then added and stirred until a homogeneous melt is obtained; the stearic acid, calcium stearate, and aluminum oxide were then added in that order. Stirring is continued to effect homogeneity and the mix cooled to 60 C., after which is poured into a siliconized, lubricated container having rectangular cavities -inch deep, l inch wide and 1% inches long. The melted wax is poured to the very top of the container and the mix allowed to cool and congeal into the tub-shaped eraser. The eraser article thus formed contains a uniform dispersion of abrasive throughout the structure.

EXAMPLE II Bruning 880 Revolute alongjvvith blueline diazo-type paper. A bluepnnt of the xerograp 1c copy which indicates no sign of the erased letter is obtained.

EXAMPLE ill The composition of Example I is prepared in the manner outlined therein with the exception that glass fibers are used as the abradant material. The heating of the resulting composition is continued at 65 C. and the melt is simultaneously cooled and extruded through a /4-inch die. The eraser article thereby formed is an elongated cylindrical stick of /4 inch diameter. The cylindrical stick is divided into 8-inch length portions. These 8 inch portions are then dipped in melted paraffin wax held at C. continuously until all but a small portion of one end of the cylindrical stick has one one-sixteenth of an inch of wax coated thereon. The resulting article is cylindrical in shape with about one-eighth of an inch of the central core abrasive composition protruding from one end.

The protruding end of the article is applied to a translucent vellum copy from a Xerox 1824 in the same manner outlined in Example II. It is found that not only is there no raising of fibers but, in addition, the abraded area is smoothed by the wax casing which is also applied in the process of rubbing. A blueprint of the xerographic vellum copy has the same quality as indicated in Example ll.

While the invention has been described in terms of a preferred embodiment it is to be understood that those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation of material for teaching of an invention without departing from its essential teachings.

What is claimed is:

1. An eraser composition useful in removing toner from translucent vellum xerographic copy paper comprising a solid wax matrix containing an abrasive selected from the group consisting of fused aluminum oxide powder, powder pumice, silica and glass fibers, said abrasive being uniformly distributed in a concentration of about 10-40 percent of said wax matrix and having a maximum mesh size of about 300 and additionally comprising about 20 percent by weight of stearic acid and about 5 percent by weight of calcium stearate.

2. An eraser composition of claim 1 in which the abrasive in silica in a concentration of about 30 percent.

3. An eraser composition of claim 1 in which the abrasive is glass fibers in a concentration of about 30 percent.

4. An eraser composition of claim 1 in which the abrasive is aluminum oxide in a concentration of about 30 percent.

5. A method of erasing translucent vellum xerographic copy paper comprising:

a. providing the eraser composition of claim 1, and

b. applying the composition by means of rubbing so as to effect removal of toner on the translucent vellum xerographic copy paper. 

2. An eraser composition of claim 1 in which the abrasive in silica in a concentration of about 30 percent.
 3. An eraser composition of claim 1 in which the abrasive is glass fibers in a concentration of about 30 percent.
 4. An eraser composition of claim 1 in which the abrasive is aluminum oxide in a concentration of about 30 percent.
 5. A method of erasing translucent vellum xerographic copy paper comprising: a. providing the eraser composition of claim 1, and b. applying the composition by means of rubbing so as to effect removal of toner on the translucent vellum xerographic copy paper. 